Shoe sole construction with flexible shank



J. SCHALLER ETAL 3,067,752

SHOE SOLE CONSTRUCTION WITH FLEXIBLE SHANK 4 Sheets-Sheet 1 Dec. 11, 1962 Filed Jan. 2, 1959 INVENTOR'S Jb/IANNES SCH/LL52 kaazkr BEAM! ArrvfNE KS Dec. 11, 1962 J. SCHALLER ETAL 3,067,752

SHOE SOLE CONSTRUCTION WITH FLEXIBLE SHANK 4 Sheets-Sheet 2 Filed Jan. 2, 1959 Fig. 4-

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kwglvrms JOHNVNE-S QIIALLE? Dec. 11, 1962 J, sc R ETAL 3,067,752

SHOE SOLE CONSTRUCTION WITH FLEXIBLE SHANK Filed Jan. 2, 1959 4 Sheets-Sheet s I v Fig. 11

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INVENIORS JOHANNES SCI/A1456 Dec. 11, 1962 J. SCHALLER ETAL SHOE SOLE CONSTRUCTION WITH FLEXIBLE SHANK /NVNTORS JUHANA/ES .SZ'HAZLE P M5537 WV 5) ATTORNEY 3,%7,752 Patented Dec. 11, 1962 fire 3,067,752 SHGE LE CGNS'lRUfITION WITH FLEXIBLE SHANK Johannes Schaller, Gffenbach (Main), and Robert Brawn,

Kleve, Rhineland, Germany, said Rrauu assignor to said dchaller Filed Jan. 2, 1955 Ser. No. 784,802 Claims priority, application Germany Jan. 7, 1958 20 tClaims. (Cl. 128-586) The present invention relates to improvements in shoes. More particularly the invention is directed to improvements in the construction of shoe soles for obtaining increased flexibility at the shank and reduced resistance to torsional stresses about an axis generally lengthwise of the shoe. As described hereinafter, the term sole has been used generically with respect to both insoles and outsoles, inasmuch as the invention may be embodied in either or both.

It has already been known prior to this invention to provide the shank portion of insoles and/or outsoles of shoes with cutouts extending inwardly from the edges of the soles and to fill these cutouts with inserts of a softer material than that of which the respective sole is made. The width of the sole which is provided with such inserts at the area of the shank portion corresponds approximately to the size which is determined by a vertical projection of the foot, the soles being only slightly narrowed down at the shank portion. Near the edges of the sole, the prior art cutouts were made wider than at the inner end so that each cutout had substantially a hyperbolic shape. Although a sole of such a design permits the heel part to be properly twisted and bent relative to the toe part, it has the disadvantage that it is difficult to secure it properly to the other parts of the shoe.

It is an object of the present invention to provide a sole for a shoe of the general type as described above which is easily secured to other parts of the shoe and is particularly designed to increase the ability of the heel part to be twisted and bent relative to the front part of the sole. The present invention provides a plurality of cutouts at each sole edge which are arranged in such a manner that the surfaces defining each cutout extend substantially parallel to each other and that each cutout has a width at least corresponding to the thickness of the sole. The term cutout as it is used in connection with the present invention refers to the space extending through the entire thickness of the sole where the sole material has been removed. A sole of a design according to this invention can, when embodied in a shoe, easily follow the movements of the foot and does not interfere with such movements. When walking with such a shoe, the distance between the surfaces defining the cutouts may then either increase or decrease near the sole edges, depending upon whether these cutouts extend inwardly from the outer or inner edge of the sole. Each cutout is preferably filled with a material which is more elastic than the material of the main portion of the sole itself in which the cutouts are formed. This filling material may be foam rubber or a material of similar properties. This elastic filling material in the sole cutouts is preferably made integral with a foot cushioning layer which is shaped in accordance with the shape of the sole of the foot. However, such a cushion may also consist of a different kind of elastic material than that filling out the cutouts in the sole.

If a sole, especially an insole, is designed at the area of the shank portion so as to be capable of twisting and bending or to be wrung, it is the prevailin opinion that this is of value only in a heelless shoe, such as a tennis shoe or the like. Such a shoe is therefore only intended for protecting the foot from injury from the outside. The application of such a twistable shank portion has thus heretofore been deemed of no use in heeled shoes because experience has shown that the shank portion of such shoes, if not provided with a built-in rigid arch support, will be bent down by the foot. It has therefore become the modern trend to make such shank portions more and more rigid. These rigid shank portions have been provided in shoes with a relatively flat insole as well as in shoes with a cushioning layer. In view of this trend it would appear senseless to a person familiar with the art to provide a shoe which contains a cushioning layer with a soft shank portion.

Extensive experiments recently made have, however, shown that the object of the invention may be successfully attained if a sole, especially an insole, which is provided with a plurality of cutouts within the shank portion is equipped with a cushioning layer of such a shape that the rear part of the heel cavity will be symmetrical up to the tread point of the heel bone, while the heel cavity will otherwise be made of such an unsymmetrical shape that the inner edge of the bulge at the front end of the heel cavity will be of a greater height than the outer edge thereof, and that the upper surface of the front part of the insole will increase in height from the inner side of the foot to the outer side thereof in accordance with the height of the heel used.

Such a design of the sole, and especially of the insole, according to this invention avoids any rigidity within the shank portion when the shoe follows the movements of the foot in walking. The foot will then be positioned in a most desirable erect position, and not merely in the standing position, but, it will retain its best possible position even in walking. This combination of the abovementioned features supports and strengthens the muscular system of the foot and the lower part of the leg and permits the same to act without interference so that the arch of the foot will be prevented from bending down and the shank portion of the shoe will then likewise not be bent down. In this connection, it is an important fact that the cutouts which are provided of a relatively narrow width as compared to their length within the area of the shank portion and are filled with a very elastic material permit a compression thereof adjacent to the inner edge of the sole and an extension thereof adjacent to the outer edge of the sole so that the heel portion may not only be raised and lowered relative to the front part of the sole, but also be twisted inwardly in a movement transverse to the longitudinal direction of the sole.

This may be more easily understood by the following considerations:

A normal foot carrying a heeled shoe with a sole member having a flat surface at the front and heel footengaging parts thereof assumes, when standing, a definitely faulty position as the spaces between the joints are then unduly enlarged at one side and the bones which are linked to the big toe are arched upwardly. In the walking movement, a normal foot has the tendency to bend as well as to twist. If the sole member is flat at the front and rear parts thereof and provided with a rigid shank portion, the foot will be prevented from assuming a proper erect position. This will also be true even though the rigid shank portion is omitted from the shoe.

If, however, the sole, and especially the insole, is designed according to the invention, the foot will be given, prior to walking movement, a starting position in accordance with the height of the heel which prevents the faulty position of the foot when standing. In the subsequent rolling action of the shod foot when walking, the heel upon being lifted will turn inwardly, i.e., the heel will turn so that its bottom surface faces more inwardly with the outside edge thereof moving downwardly with respect to the inside edge, and at the same time the heel will draw closer to the ball of the big toe. If the sole is thus designed, the foot will not be hampered by the shoe. Since this will automatically insure the required erect position of the foot, there is no danger that the shank portion of the shoe will be bent down and that the shoe heel will thereby be bent back toward the rear. This danger of the shoe heel being bent back only arises if the shank of the shoe is made soft as prescribed according to the invention and if the sole or insole is not provided with a resilient cushion, but is made substantially level. Such bending of the shoe heel increases in a shoe of the kind as described in accord ance with the height of the heel.

A further improvement may be attained by providing the foot-engaging face of the sole with an aperture at least within the area of the ball of the big toe and by filling such aperture partly or entirely with a material which is more elastic than that of the sole itself. In order to permit the cushioning layer to be made as thin as possible, the lowest point of the contact area of the ball of the big toe should then be lower than the upper adjacent surrounding surface of the sole itself before the cushion is attached thereto. A further improvement will be attained by also providing an aperture within the heel area of the sole and by likewise filling this aperture partly or entirely with a material of greater elasticity than that of the sole itself. Also, in this case, the lowest point of the heel cavity should be placed lower than the upper surface of the adjacent surrounding area of the heel portion of the sole itself.

In addition to the apertures as described above, the sole may also be provided at the points of contact of the pads of the toes with one or more apertures which are likewise filled partly or entirely with a material of greater elasticity than that of the sole itself. This elastic material may be even more elastic than the material which is combined by vulcanization with the relatively fiat-surfaced sole and forms the elevations and recesses of the foot cushion and which latter material should also fill the cutouts which are provided within the area of the shank portion of the sole. However, if desired, these latter cutouts may likewise be filled with a material which is still more elastic than that forming the foot cushion.

These and further objects, features, and advantages of the present invention will become more apparent from the following detailed description thereof, particularly when read with reference to the accompanying drawings, in which FIGURE 1 shows a plan view of a sole structure, the shank portion of which is provided with a plurality of cutouts of a certain uniform width extending inwardly from the edges of the sole;

FIGURE 2 shows a plan view of a sole for use either as an insole or an outsole or as a single structure in place of both and similar to that according to FIGURE 1, but in which the cutouts at the opposite sides of the sole are staggered relative to each other and are filled out by a material which is more elastic than that of the insole itself;

FIGURE 3 shows a plan view of a sole for use either as an insole or an outsole or as a single structure in place of both and in which the cutouts which are filled with an elastic material extend at both sides beyond the shank portion;

FIGURE 4 shows a plan view of a sole structure which may be used as an insole or also as a complete sole providing an outer wear surface, the surface of which sole facing toward the foot is provided with an elastic layer of a shape in accordance with the shape of the sole of the foot;

FIGURE 5 shows a plan view of a sole structure which may be used as an insole or also as a complete sole pro- 4 viding an outer wear surface according to a modification of that shown in FIGURE 4;

FIGURE 6 shows a plan view of the lower side of a sole structure which may be used as an insole or also as a complete sole providing an outer wear surface according to the invention;

FIGURE 7 shows a cross section taken along line VIIVII of FIGURE 6;

FIGURE 8 shows a cross section taken along VIIIVIII of FIGURE 6;

FIGURE 9 shows a cross section taken along IX-IX of FIGURE 6;

FIGURE 10 shows a cross section taken along a line XX of FIGURE 6';

FIGURE 11 shows a cross section taken along IXl of FIGURE 6;

FIGURE 12 shows a cross section taken along line XlI-XII of FIGURE 6;

FIGURE 13 shows a cross section taken along III-XIII of FIGURE 6; while FIGURE 14 shows a cross section taken along XIVXIV of FIGURE 6.

From the following discussion, it will be obvious that the sole members of FIGURES 1 through 3 may be used either as an insole or as a wearing sole or as a single member in place of both, whereas the sole members of FIG- URES 4 through 14 are constructed for supporting the foot and may be utilized either as insoles or as soles which both support the foot and provide at their opposite face a wearing surface. If the illustrated structures form only a portion of the sole construction, it is neces sary only that the additional insole or outsole used there with be provided with sufiicient flexibility so as not to substantially impair the flexibility achieved by the cutouts in the sole members in accordance with this invention.

Referring to the drawings, and first particularly to FIGURE 1, the sole member 1 is provided within the shank portion with cutouts 4 and 5 extending inwardly from the edges 2 and 3, respectively, and having difierent lengths but a substantially equal width. However, the width of each individual cutout 4 and 5 does not have to be exactly uniform throughout its length. It will be apparent from FIGURE 1 that the cutouts 4 and 5 extend through the entire thickness of the sole member 1, and such is true of all cutouts of the other embodiments of the invention illustrated herein, although some of these cutouts are shown to be filled with an elastic material as is described hereinafter.

While the cutouts 4 of the sole member 1 according to FIGURE I extend in the same direction as the corresponding cutouts 5, the cutouts 6 and 7 of sole member 8 according to FIGURE 2 are staggered relative to each other so that cutouts 6 terminate between cutouts 7, or vice versa. However, the staggered cutouts according to FIGURE 2 may also be made of a length similar to cutouts 4 and 5 in FIGURE 1. All of these cutouts are filled with a material 9 of greater elasticity than that of the main body of sole members 1 or 8.

Particularly in those cases in which the sole member is to be provided with a resilient layeror cushion which is shaped according to the sole portion of the foot, it is advisable as illustrated in FIGURE 3 to provide the cutouts not only within the area of the shank, but also within the toe and heel portions adjacent to and at both ends of the shank portion. The cutouts 12 and 13 in the sole member 10 are likewise filled with an elastic material 11 and are arranged similarly to those in FIGURE 1 so that each cutout 12 at one side of sole member 10 extends in the same direction as the corresponding cutout 13 at the other side. However, cutouts 12' and 13 do not have to be parallel, but may extend at an acute angle to each other, as indicated in the toe area of the sole member.

If a sole member according to the invention is to be covered with a resilient layer or cushion which is shaped line line

line

line

line

according to the sole portion of the foot, it is advisable to fill out the cutouts in the sole member with the same material as that of which the resilient layer is made. This is illustrated in FIGURE 4. The sole member 14 which is provided with cutouts 12 and 13 similarly as shown in FIGURE 3 and which may consist of leather, a composition, plastic, or the like is combined by vulcanization with a layer 15, for example, of a very fine foam rubber, also called moss rubber, which also fills the cutouts 12 and 13 so that the sole member, the elastic filling in the cutouts, and the layer 15 which is shaped according to the sole portion of the foot all form one integral unit to which a thin cover sheet or sock lining 16 may also be applied. FIGURE illustrates that the sole member 17 may also be provided with a foot cushion 18 of a different shape than that shown in FIGURE 4. The cover sheet 16 of FIGURES 4 and 5 may only partially cover the foot cushions 15 and 18 from the heel portion up to a point near the ball of the foot and the foot cushion 15 or 18 may extend somewhat further toward the toe portion of the sole, but terminating short of the tip thereof.

FIGURES 6 to 14 illustrate a sole member 19 which is made, for example, of leather or' a composition consisting of fibers which are impregnated with a binding agent, or of a plastic such as polyvinyl chloride. This sole member 19 is likewise provided at the area of the shank portion with cutouts 20 of width greater than the thickness of sole member 19 and extending through the entire thickness of the sole member. These cutouts are filled with the same material which also forms the foot cushion, although they may also be filled with a material which is still more elastic than that of which the foot cushion is made. Sole member 19 is further provided with an aperture 21 at the area of contact of the ball of the big toe, with an aperture 22 at the area of contact of the heel of the foot, and an aperture 23 at the area of contact of the pads of the toes. These apertures 21, 22, and 23 may be likewise filled with the material forming the foot cushions. However, it is advisable to fill at least the apertures 21 and 22 with a still more elastic material than the foot cushion material, although, as seen from the standpoint of manufacture, it would obviously be the simplest procedure to fill out all cutouts 20 and the apertures 21, 22, and 23 with the same material which forms the footcushion.

As illustrated in the cross sections according to FIG- URES 7 to 14, sole member 19 is provided with a foot cushion of a shape which has been determined by a large series of tests and experiments and has proved to be the best possible from an anatomical standpoint. FIGURES 7 to show that the upper surface of the cushion at the central part of aperture 21 is disposed at a lower level than the upper side of the adjacent surrounding area of sole member 19 itself without the cushion. This also applies to the heel cavity, as illustrated particularly in FIGURES 13 and 14. The other surfaces of the cushion lie within sole member 19 or above the upper surface thereof. Although the sole member may also be designed so that the lowest points of the cushion, that is, those within the area of contact of the ball of the big toe or the heel, are level with the upper adjacent surrounding surface of the sole member itself, this has the disadvantage that the thickness of the cushion will be thereby increased. It will also be seen from the drawings that the cushion 23 of the toe portion of the sole member will be level as long as it does not have to bear the load of the foot. FIGURES 9 and 10 show that between the toe and shank portions the outer edge 24 of the sole member is disposed at a higher level than the inner edge 25', while within the area of the shank portion, both edges are disposed at substantially the same level, as shown in FIGURE 11. At the area of the front end of the heel portion, as indicated at 26 in FIGURE 14 the inner edge 25 of the cushion on the sole member is higher than the outer edge 24 (FIGURE 12), while both edges are of equal height at the area of the tread points of the heel as shown in FIGURE 13. Consequently, the rear part of the heel cavity is of a symmetrical shape up to the tread point of the heel bone.

Although our invention has been illustrated and described with reference to the preferred embodiments thereof, we wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed our invention, what We claim is:

l. A sole construction for a shoe having at least one sole with a plurality of cutouts within the area of the shank extending inwardly from the opposite sole edges and through the entire thickness of the sole, the surfaces defining each of said cutouts being substantially parallel to each other, and the width of said cutouts being at least equal to the thickness of said one sole.

2. A sole construction for a shoe as defined in claim 1, further comprising a plurality of inserts at least partly filling said cutouts in said sole and consisting of a material having a greater elasticity than the material of said sole.

3. A sole construction for a shoe as defined in claim 2, further comprising a foot cushion on said sole having a shape in compliance with the shape of the sole portion of a foot and integrally connected to the material of said inserts filling said cutouts.

4. A sole construction for ashoe as defined in claim 3, wherein said foot cushion has a heel cavity with a bulge limiting the forward end thereof, the rear part of said heel cavity being of a symmetrical shape up to the tread point of the heel bone of a foot, said heel cavity being otherwise of an unsymmetrical shape having an inner edge of a greater height than the outer edge of said bulge, the upper surface of the front part of said insole with said cushion thereon starting from the inner foot side being of an increasing height in accordance with the height of the heel on said shoe.

5. A sole construction for a shoe as defined in claim 2, wherein said sole has an aperture therein at least within the area corresponding to the ball of the big toe, said aperture being at least partly filled with a material of greater elasticity than the material of said sole itself.

6. A sole construction for a shoe as defined in claim 5, wherein the lowest upper-surface point of said filled aperture in said sole is disposed lower than the upper adjacent surrounding surface of the sole itself, said sole having otherwise a substantially uniform thickness at all sides thereof.

7. A sole construction for a shoe as defined in claim 2, wherein the heel portion of said sole has an aperture therein, said aperture being at least partly filled with a material of greater elasticity than the material of said sole itself.

8. A sole construction for a shoe as defined in claim 7, wherein the lowest upper-surface point of said filled aperture in said heel portion of said sole is disposed lower than the upper adjacent surrounding surface of the sole itself.

9. A sole construction for a shoe as define-d in claim 2, wherein said sole has at least one aperture therein within the area of contact of the toe pads of a foot, said aperture being at least partly filled with a material of greater elasticity than the material of said sole itself.

10. A sole construction for a shoe as defined in claim 2, further comprising a foot cushion on said sole having a shape in compliance with the shape of the sole portion of a foot, the material of said inserts filling said cutouts in said sole having a greater elasticity than the material of said foot cushion which, in turn, is more elastic than the material of said sole itself.

11. A sole construction for a shoe as defined in claim 2, further comprising a foot cushion on said sole having a shape in compliance With the shape of the sole portion of a foot and consisting of a material more elastic than the material of said sole itself, said sole further having at least one aperture therein at least Within the area corresponding to the tread point of the heel bone of a foot, said aperture being at least partly filled with the same kind of material as that of said inserts in said cutouts, said material in said cutouts and said aperture being more elastic than the material of said foot cushion.

12. A sole construction for a shoe as defined in claim 2, further comprising a foot cushtion on said sole having a shape in compliance with the shape of the sole portion of a foot and consisting of a material more elastic than the material of said sole itself, said material of said cushion also filling said cutouts in said sole and being integral therewith.

13. A sole construction for a shoe as defined in claim 2, further comprising a foot cushion on said sole having a shape in compliance with the shape of the sole portion of a foot and consisting of a material more elastic than the material of said sole itself, said sole further having apertures therein at least within the areas corresponding to the tread points of the heel bone and the ball of the big toe of a foot, said material of said cushion also at least partly filling said cutouts and said apertures in said sole and being combined with said sole by vulcanization.

14. A sole construction for a shoe as defined in claim 2, wherein said sole has an aperture within the area corresponding to the ball of the big toe, and another aperture in the heel portion, said apertures and said cutouts being at least partly filled with said material of greater elasticity than the material of said sole itself.

15. A sole construction for a shoe as defined in claim 2, wherein said sole has an aperture within the area corresponding to the ball of the big toe, another aperture in the heel portion, and at least one aperture within the area of contact of the toe pads of a foot, all of said apertures and cutouts being at least partly filled out with said material of greater elasticity than the material of said sole itself.

16. A sole construction for a shoe as defined in claim 2, further comprising a foot cushion on said sole having a shape in compliance with the shape of a sole portion of a foot, said sole having apertures within the areas corresponding to the tread points of the heel bone, the ball of the big toe, and the toe pads of a foot, said elastic material filling said cutouts in said sole also at least partly filling said apertures and also forming said cushion.

17. A sole construction for a shoe having at least one sole with a plurality ofpcutouts within the area of the shank and extending inwardly, generally transversely of the longitudinal dimension of the shoe, from each of the opposite sole edges, said cutouts extending through the entire thickness of said sole and being generally elongated to provide reduced resistance to torsional stresses about an axis generally lengthwise of the shoe as well as providing increased flexibility of said sole at its shank portion.

18. A sole construction for a shoe as designed in claim 17, further comprising a plurality of inserts at least partly filling said cutouts in each said sole and consisting of a material having a greater elasticity than the material of said sole.

19. A sole construction for a shoe having an outer wearing sole with a plurality of cutouts Within the area of the shank and extending inwardly, generally transversely of the longitudinal dimension of the shoe, from each of the opposite sole edges, said cutouts extending through the entire thickness of said outer sole and being generally elongated to provide reduced resistance to twisting of the heel portion of the sole with respect to the toe portion thereof as Well as providing increased flexibility of said sole at its shank portion.

20. A shoe sole construction comprising an insole with a plurality of cutouts within the area of the shank and extending inwardly, generally transversely of the longitudinal dimension of the shoe, from each of the opposite edges of the insole, said cutouts extending through the entire thickness of said insole and being generally elongated to provide reduced resistance to twisting of the heel portion of the insole with respect to the toe portion thereof as Well as providing increased flexibiliy of said insole at its shank portion.

References Cited in the'file of this patent UNITED STATES PATENTS 1,021,441 Austin Mar. 26, 1912 1,841,942 Fenton Jan. 19, 1932 2,008,985 Lattemann July 23, 1935 2,185,993 Haskell Jan. 2, 1940 2,220,439 Block Nov. 5, 1940 2,253,959 Margolin Aug. 26, 1941 2,323,579 Vigorith July 6, 1943 2,369,531 Caltabiano Feb. 13, 1945 2,862,313 Jones Dec. 2, 1958 2,863,231 =Jones Dec. 9, 1958 FOREIGN PATENTS 1,108,501 France Aug. 31, 1955 530,238 Germany Aug. 12, 1930 

